- Provides Stability to the Scheduling Process
- Maximizes Customer Service With Realistic Available-to-Promise Dates
- Improves Accuracy of Shop Floor Schedule
- Improves Vendor Delivery Performance
This module provides the master scheduler with the necessary tools to efficiently define and maintain schedules for all MPS items defined for a site. One of the most significant capabilities of the MPS module is its ability to effectively generate and integrate realistic schedules with minimal manual intervention. The schedule becomes a major driving factor in the development, execution, and control of the business plan for the organization.
Master Scheduling Item Identification
The master scheduler’s most significant implementation task is identifying those items that should be master scheduled and developing the first trial schedule for those items. Initially, the MPS items would be identified for existing product lines. As the company introduces new products and phases out older or unprofitable product lines, this list of MPS items would be updated.
Developing the Trial Schedule
The trial schedule consists of trial orders with due dates that should be beyond the planning time fence. The initial trial schedule is developed for the MPS items from the demands placed on the factory. The MPS and trial schedules are then compared to the existing demand on an iterative basis. After each iteration, the trial schedule can be amended.
The master scheduler is responsible for reviewing the various inputs to be taken into consideration and defining the first cut trial schedule.
- Sales forecasts
- Customer orders
- Branch warehouse demands
- Intracompany orders
- Management decisions
The Master Scheduler is responsible for reviewing the various inputs to be taken into consideration and defining the first cut trial schedule. The requirements are then compared to the MPS and trial schedules during the planning run. The comparison will produce action messages to assist the Master Scheduler in amending the trial schedule before the next planning iteration.
The trial schedule is reviewed and approved prior to becoming the Master Production Schedule. When the schedule is accepted by management, it is then released as the live production schedule and the Available-To-Promise report can be produced. When releasing the trial schedule, the system automatically converts trial order an trial demand into firm planned MPS orders and dependent demand that will drive the Requirement Planning process.
Net Change Processing
While a planning run that is processed in a regenerative mode processes all MPS item, planning run iterations can occur on a “net change” basis to improve throughput performance. As the trial schedule for an item is manually amended, the item and its components will be scheduled to be included in the next planning run.
If a net change planning run is subsequently requested, any item whose trial schedule or planning parameters have changed since the previous run will be selected for processing. The planning run automatically resets the ‘scheduled’ indicator after processing an item, whether it is a net change run or a regeneration.
A regeneration run discards all prior action messages for each MPS item, replans all MPS items, and generates a new list of action messages. A net change run only discards the action messages for the MPS items that are to be re-planned. However, the Action Message report will be a complete compilation of all action messages, even if the item was not re-planned during the net change run.
This capability provides the Master Scheduler with a complete list of all action messages through the last iteration; thereby, eliminating the annoying situation of having to deal with a separate Action Message report for each run.
Planning Time Fence
A planning time fence is defined by APICS as “A policy or guideline established to note where various restrictions or changes in operating procedures take place. For example, changes to the master schedule can be accomplished easily beyond the cumulative lead time whereas changes inside the cumulative lead time become increasingly more difficult to a point where changes should be resisted.”
The planning time fence is used to minimize rescheduling and becomes the master scheduler’s override to the composite (cumulative) lead time. This becomes particularly useful, in fact required by the system, when the composite lead time has not yet been established for an MPS item.
Since the planning time fence is generally equal to the item’s composite lead time, the composite lead time will be used by the system as the planning time fence when the planning time fence value is zero (0). Defaulting to the composite lead time should help to minimize the master scheduler’s manual intervention.
Demand Time Fence
The planning run also utilizes an optional demand time fence on a per item basis, again, with a default to minimize manual intervention. The default for the demand time fence is established on a global basis for all items when the MPS planning run is requested.
The objective of the demand time fence is to eliminate the impact of forecasts on the MPS in the near term. This is based on the fact that actual product demand is more accurate than a forecast and thus gives a truer picture of factory demands. Since “the near term” is variable from plant to plant and product to product, this time fence should only be implemented after careful review of the MPS items.
Variable Period Lengths
The time periods associated with the trial schedule are variable by item. This allows the Master Scheduler to establish the trial schedule in monthly periods for some items, in weekly periods for others, and in daily periods for a third group of items if desired.
The trial schedule is reviewed and approved prior to becoming the Master Production Schedule. When the schedule is accepted by management, it is then released as the live production schedule and an Available-To-Promise report can be produced. When releasing the trial schedule, the system automatically converts trial orders and trial demand into firm planned MPS orders and dependent demand.